Background: Recent reports on the use of hydroxychloroquine (HCQ) alone, or combined with azithromycin (AZM) in the management of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have raised cardiac safety concerns. Currently, there is limited mechanistic data evaluating cardiac safety with HCQ and AZM therapy. Methods: Using comprehensive In Vitro ProArrhythmia Assay (CiPA) Schema IC50 paradigms, we examined the cardiac electrophysiological effects of HCQ and HCQ/AZM. Molecular modelling explored HCQ and AZM binding properties to hERG. Langendorff-perfused guinea-pig hearts were electrically and optically mapped by multi-electrode array and voltage (RH237) and Ca2+ (Rhod-2 AM) dyes. Human action potential and ion current reconstructions were performed in silico. Results: HCQ blocked IKr and IK1 with IC50 concentrations (10+-0.6 and 34+-5.0 microM) within the therapeutic range observed clinically. HCQ also blocked INa and ICaL but at higher IC50, whilst Ito and IKs were unaffected. Contrastingly, AZM produced minor inhibition of INa, ICaL, IKs, and IKr,, with no effect on IK1 and Ito. HCQ + AZM combined inhibited IKr and IK1 with IC50s of 7.7 +- 0.8 microM and 30.4 +- 3.0 microM, but spared INa, ICaL and Ito,. Molecular modelling confirmed potential HCQ binding to hERG. Cardiac mapping and ECG studies in isolated hearts demonstrated that HCQ slowed heart rate and ventricular conduction with associated prolongation of PR, QRS and QT intervals. Optical mapping demonstrated, and prolonged, more heterogeneous, action potential durations and intracellular Ca2+ transients. These effects were accentuated with combined HCQ+AZM treatment, which elicited electrical alternans, re-entrant circuits and wave breaks. Reconstruction in a human in-silico model demonstrated that this is attributable to the integrated action of HCQ and AZM reducing IKr, IKs and IK1. Conclusions: These data provide an electrophysiological basis for recent FDA guidelines cautioning against combined HCQ/AZM administration for the treatment of Covid-19 on the grounds of potential cardiac safety. We would strongly recommend monitoring of electrocardiographic QT interval with the use of this combination of medications.

中文翻译：

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羟氯喹和阿奇霉素治疗COVID-19的心律失常的机制研究

背景：最近有关单独使用羟氯喹（HCQ）或与阿奇霉素（AZM）联合使用来治疗严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的报道引起了心脏安全性问题。目前，评估HCQ和AZM治疗心脏安全性的机制数据有限。方法：使用全面的体外心律失常分析（CiPA）模式IC50范例，我们检查了HCQ和HCQ / AZM的心脏电生理效应。分子建模探索了HCQ和AZM与hERG的结合特性。用多电极阵列和电压（RH237）和Ca2 +（Rhod-2 AM）染料对Langendorff灌注的豚鼠心脏进行电学和光学成像。人类动作电位和离子电流重建在计算机上进行。结果：HCQ用IC50浓度（10 + -0。）阻断IKr和IK1。在临床观察到的治疗范围内为6和34 + -5.0 microM）。HCQ也阻止了INa和ICaL，但IC50较高，而Ito和IK则不受影响。相反，AZM对INa，ICaL，IKs和IKr产生较小的抑制作用，而对IK1和Ito没有影响。HCQ + AZM联合抑制IKr和IK1，IC50为7.7±0.8 microM和30.4±3.0 microM，但保留了INa，ICaL和Ito。分子建模证实了潜在的HCQ结合hERG。在离体心脏中进行的心脏作图和心电图研究表明，HCQ会减慢心率和心室传导，并伴有PR，QRS和QT间隔的延长。光学测绘表明并延长了异质性，动作电位的持续时间和细胞内Ca2 +瞬变。HCQ + AZM联合治疗会引起电交替信号，从而加剧了这些影响，折返电路和波浪中断。在人类计算机模型中的重建表明，这归因于HCQ和AZM的综合作用降低了IKr，IKs和IK1。结论：这些数据为最近的FDA指南提供了电生理基础，警告以潜在的心脏安全为由，禁止联合HCQ / AZM联合治疗Covid-19。我们强烈建议您使用这种药物组合监测心电图QT间隔。这些数据为最近的FDA指南提供了电生理基础，该指南警告以潜在的心脏安全为由，禁止联合HCQ / AZM联合治疗Covid-19。我们强烈建议使用这种药物联合监测心电图QT间隔。这些数据为最近的FDA指南提供了电生理基础，该指南警告以潜在的心脏安全为由，禁止联合HCQ / AZM联合治疗Covid-19。我们强烈建议使用这种药物联合监测心电图QT间隔。